In the field of communication technologies, multiband is always a development tendency for mobile communication. A mobile terminal in the prior art such as an antenna system of a mobile phone includes a rear shell and a frame, and a clearance region is defined between the rear shell and the frame. Due to the influence of the volume of the mobile terminal, the clearance region is small. Besides, for a metal frame antenna structure in the prior art, an upper antenna includes a diversity antenna and an NC antenna, and the diversity antenna occupies most of the metal frame, and thus there is little space left for the radiator of the NC antenna. In other words, the NC antenna should be as short as possible under the premise of guaranteed performance so as to guarantee performance of the diversity antenna. Therefore, the radiator for the NC antenna has a limited length, which makes it difficult to simultaneously cover bands of GPS, WIFI 2.4G, and WIFI 5G, especially WIFI 5G band. However, the application of WIFI 5G will be a development tendency in the field of communication technologies. Therefore, it is necessary to provide an antenna system as soon as possible which can cover GPS, WIFI 2.4G, and WIFI 5G at the same time.